Method and apparatus for scanning X-ray tomography

A method of producing a tomographic image of an area within a subject comprising the steps of:

• traveling an X-ray origin point through a raster scan which includes a plurality of parallel scan lines,
• detecting X-ray intensity during the course of said raster scan at a plurality of spaced apart detection points situated at the opposite side of said subject from said X-ray origin point and producing a plurality of signal sequences each of which defines a successive series of values that differ from each other in accordance with variations of X-ray intensity at an associated one of said detection points at successive times during the course of the same raster scan,
• combining signal values from each of said sequences that originate at predetermined different times in the course of said raster scan to produce a sequence of tomographic image signal values, and
• producing said tomographic image by traveling a light origin point through a raster scan similar to said raster scan of said X-ray origin point while modulating a characteristic of the light emitted at said light origin point in accordance with said sequence of tomographic image signal values.

In tomographic imaging apparatus having an X-ray source wherein a charged particle beam is directed to a target surface to generate X-rays at an X-ray origin point at said surface and which has beam deflection means for moving said origin point through a raster scan at said surface, a plurality of X-ray detectors which are spaced apart from said source and positioned to detect X-rays at separate detection points that are spaced apart from each other, said detectors including a first detector which transmits a first sequence of data values that is indicative of variations of X-ray intensity at a first of said detection points at successive times during the course of said raster scan and at least a second detector which transmits a second sequence of data values that is indicative of variations of X-ray intensity at a second of said detection points at successive times during the course of the same raster scan, the improvement comprising:

• means for combining individual data values from said first detector that are generated by X-rays from successive particular locations in said raster scan with individual data values of at least said second sequence that are generated by X-rays from predetermined successive different locations in the same raster scan in order to produce a composite sequence of data values, and
• means for displaying an image corresponding to at least a portion of said raster scan which depicts variations of the magnitude of successive data values of said composite sequence.

Apparatus for producing a tomographic image of a predetermined plane within a subject comprising:

• an X-ray source having means for traveling an X-ray origin point through a raster scan which includes a plurality of sequential parallel scan lines,
• a plurality of X-ray detectors spaced apart from said source and being positioned to detect X-rays at detection points which are spaced apart in a direction parallel to the plane of said raster scan, each of said detectors having means for generating a signal during the course of each raster scan line in accordance with variations of the detected X-ray intensity at successive times during the course of the raster scan line,
• means for digitizing said detector signals to produce a plurality of primary sequences of data values,
• means for adding individual data values from each of said primary sequences that originate at predetermined different times during the course of said raster scan to produce a sequence of composite data values,
• a display device having means for displaying an image corresponding to at least a portion of said raster scan by traveling a light origin point along a plurality of sequential parallel scan lines, and
• means for modulating said light origin point during said travel thereof along said parallel scan lines in accordance with variations of the successive data values of said composite sequence of data values.